Reversible Control of Gelatin Hydrogel Stiffness by Using DNA Crosslinkers*

Area of Science:

• Biomaterials Science
• Molecular Engineering
• Regenerative Medicine

Background:

• Dynamically tunable biomaterials are essential for advanced applications in regenerative medicine and cell biology.
• Controlling hydrogel properties like stiffness is crucial for mimicking native tissue environments.

Purpose of the Study:

• To demonstrate the reversible control of gelatin methacrylate (GelMA) hydrogel stiffness using DNA crosslinkers.
• To explore the potential of DNA to orthogonally control hydrogel stiffness and ligand presentation.

Main Methods:

• Replacing inter-GelMA crosslinks with double-stranded DNA (dsDNA).
• Utilizing toehold-mediated strand displacement to remove and restore dsDNA crosslinks.
• Measuring changes in elastic modulus (G') to quantify stiffness.
• Functionalizing gels with DNA strands for orthogonal control of crosslinking and ligand presentation.

Main Results:

• Reversible tuning of GelMA hydrogel stiffness between 500 and 1000 Pa over two cycles without performance degradation.
• Demonstrated orthogonal control of hydrogel crosslink density and a model ligand using distinct DNA displacement strands.
• Successful removal and restoration of DNA crosslinks via strand displacement.

Conclusions:

• DNA crosslinkers provide a powerful tool for dynamically and reversibly controlling the mechanical properties of protein-based hydrogels.
• This approach enables precise spatiotemporal modulation of the microenvironment for encapsulated cells.
• The findings have significant implications for developing advanced biomaterials for tissue engineering and cell behavior studies.